A pro-government activist who opposed a law punishing critics of Thailand’s monarchy was fatally shot Wednesday in the capital, police said.

The killing came as tensions continue over the political fate of Prime Minister Yingluck Shinawatra, whose foes are trying to force her from office to make way for an appointed government to implement reforms.

Police Col. Thanawat Watthanakul said Kamol Duangphasuk was shot by gunmen on a motorcycle in a restaurant parking lot in northern Bangkok. Kamol, a poet also known as Mainueng Kor Khuntee, was a member of the “Red Shirt” political movement which supports Yingluck and her brother, former Prime Minister Thaksin Shinawatra.

“At this point, we have no idea who the gunmen were or what the motive of the attack could be,” Thanawat said.

Thailand has been plagued by political strife since a 2006 military coup ousted Thaksin from office, after demonstrators accused him of corruption, abuse of power and disrespect for King Bhumibol Adulyadej. Since the coup, Thaksin’s opponents and supporters have contended for power, staging sometimes-violent street demonstrations.

Kamol was a strong opponent of Thailand’s lese majeste law, which provides up to 15 years in prison for anyone who defames the country’s monarchy. A newly formed vigilante group has threatened to hunt down people who oppose the monarchy, describing them as trash.

Kamol’s poetry had a hard political edge, and he advocated that the Red Shirts organize in a military fashion at the local level in order to protect Yingluck’s government. Yingluck faces court rulings that could force her from office, in what her supporters call a “judicial coup.”

The judiciary is seen as part of the Thai establishment, which has long been hostile to Thaksin. Thaksin’s supporters believe the country’s elite felt their privileges threatened by Thaksin’s popularity, especially among rural and underprivileged citizens who benefited from his populist programs.

More than 20 people have been killed and over 700 hurt since November in violence related to current anti-government protests